JP2011233648A - Circuit-board with mark - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit-board with a mark that enables easy identification of the mark and easily prevents the formed mark from causing an adverse effect on a substrate body.SOLUTION: A conductor pattern 30 including at least two layers of a first metal layer 36 and a second metal layer 32 that are laminated on a main surface 12a of a substrate body 12 has a mark section 20 that can be recognized from the outside. In the mark section 20, an opening 22 extending from a surface 36a of the first metal layer 36 on the side opposite to the substrate body 12 to the second metal layer 32 on the side of the substrate body 12 is formed. The opening 22 penetrates the first metal layer 36 and a bottom 22a of the opening 22 is formed from the second metal layer 32. The reflectivity of the portion of the second metal layer 32 forming the bottom 22a of the opening 22 is different from the reflectivity of a portion adjacent to the opening 22 of the surface 36a of the first metal layer 36.

Description

  The present invention relates to a circuit board with a mark, for example, a circuit board with a mark on which a mark for identifying the circuit board is formed.

  Conventionally, it has been proposed to form a mark for identifying a circuit board on the circuit board. For example, as shown in the plan view of FIG. 3, it has been proposed that marks 102 and 103 for identifying the wafer substrate 101 are directly marked on the wafer substrate 101 using a laser (see, for example, Patent Document 1). ).

JP 2007-234945 A

  However, when the wafer substrate itself is directly marked using a laser, the difference in contrast between the marking portion and its peripheral portion is small, so that it is difficult to distinguish the marking portion from its peripheral portion. Therefore, in order to recognize the mark, it is necessary to use a special optical system and a detection device. Further, a crack may be generated in the wafer substrate due to heat generated when the mark is formed by the laser, and the wafer substrate may be cracked starting from the crack.

  In view of such circumstances, the present invention is intended to provide a circuit board with a mark that makes it easy to recognize a mark and that can easily prevent adverse effects on the substrate body even if the mark is formed. is there.

  In order to solve the above-mentioned problems, the present invention provides a marked circuit board configured as follows.

  The marked circuit board includes a board body and a conductor pattern including at least two first and second metal layers stacked on the main surface of the board body. The conductor pattern has a mark portion that can be recognized from the outside. The mark portion has an opening formed from the surface of the first metal layer on the opposite side of the substrate body to the second metal layer on the substrate body side, and the opening is formed in the first metal layer. The bottom surface of the opening is formed by the second metal layer, the reflectance of the second metal layer of the portion forming the bottom surface of the opening, and the portion adjacent to the opening The reflectance of the surface of the first metal layer is different.

  In the above configuration, the reflectance of light is different between the second metal layer of the portion forming the bottom surface of the opening of the mark portion and the surface of the first metal layer of the portion adjacent to the opening. The opening can be recognized from the outside by an element or the like and can function as a mark. Mark identification is facilitated by increasing the difference between the reflectance of the second metal layer at the portion forming the bottom surface of the opening and the reflectance of the surface of the first metal layer at the portion adjacent to the opening. Can be.

  According to the above configuration, the mark is formed in the mark portion of the conductor pattern, and no mark is formed on the substrate body itself. Therefore, even if the mark is formed, it is easy to prevent an adverse effect on the substrate body. .

  Preferably, the aperture is formed by a laser. The thickness of the first metal layer of the conductor pattern is smaller than the thickness of the second metal layer of the conductor pattern.

  In this case, most of the heat generated when the opening is formed in the conductor pattern by the laser can be released through the conductor pattern, and the amount of heat transferred to the substrate body can be reduced. Thereby, it is possible to prevent an adverse effect on the substrate body due to the heat generated when the opening is formed in the conductor pattern by the laser.

  In addition, if the thickness of the first metal layer of the conductor pattern is smaller than the thickness of the second metal layer of the conductor pattern, adverse effects on the substrate body due to heat generated when holes are formed in the conductor pattern by a laser. Can be effectively prevented.

  That is, the smaller the thickness of the first metal layer of the conductor pattern, the smaller the depth of the opening, the amount of laser processing of the opening is reduced, and the amount of heat generated when the opening is formed in the conductor pattern by the laser. Can be reduced. The greater the thickness of the second metal layer of the conductor pattern, the longer the heat transfer path that is generated when holes are formed in the conductor pattern by the laser, and the more difficult the heat is transferred to the substrate body. Therefore, if the thickness of the first metal layer of the conductor pattern is smaller than the thickness of the second metal layer of the conductor pattern, the substrate body is adversely affected by the heat generated when the hole is formed in the conductor pattern by the laser. Can be effectively prevented.

  Furthermore, when the thickness of the first metal layer of the conductor pattern is smaller than the thickness of the second metal layer of the conductor pattern, it is easy to form the opening.

  That is, the laser processing depth of the opening reaching the second metal layer is smaller as the first metal layer of the conductor pattern is thinner, and the opening can be formed in a shorter time. Even when the amount of removal of the second metal layer by the laser when the opening is formed so that the second metal layer is exposed on the bottom surface of the opening varies, the thicker the second metal layer of the conductor pattern is, It is easy to prevent the bottom surface of the opening from reaching the main surface of the substrate body. Therefore, when the thickness of the first metal layer of the conductor pattern is smaller than the thickness of the second metal layer of the conductor pattern, the opening is easily formed.

  Preferably, the reflectance of the second metal layer in a portion forming the bottom surface of the opening is smaller than the reflectance of the surface of the first metal layer in a portion adjacent to the opening.

  When the reflectance of the second metal layer in the portion forming the bottom surface of the aperture is larger than the reflectance of the surface of the first metal layer in the portion adjacent to the aperture, the illumination light is the bottom surface of the aperture. The aperture cannot be recognized unless it reaches the surface of the aperture and is sufficiently reflected at the bottom of the aperture. On the other hand, when the reflectance of the second metal layer in the portion forming the bottom surface of the opening is smaller than the reflectance of the surface of the first metal layer in the portion adjacent to the opening, illumination light is applied to the opening. Even if it does not reach sufficiently, it is preferable because the opening can be easily recognized.

  Preferably, the conductor pattern includes at least one third metal layer disposed between the first metal layer and the second metal layer. In the third metal layer, an opening communicating with the opening formed in the first metal layer and the second metal layer is formed. The thickness of the third metal layer of the conductor pattern is greater than the thickness of the first metal layer of the conductor pattern. The reflectance of the third metal layer in the portion forming the opening is smaller than the reflectance of the surface of the first metal layer in the portion adjacent to the opening.

  In this case, it is easy to ensure the bonding strength between the metal layers of the conductor pattern.

  When an opening is formed in a conductor pattern by a laser, the heat generated when the opening is formed by the laser is more difficult to be transmitted to the substrate body by the third metal layer, so the opening is formed by the laser. The adverse effect on the substrate body due to the heat generated sometimes can be prevented more effectively.

  When the reflectance of the second metal layer in the portion forming the bottom surface of the opening is smaller than the reflectance of the surface of the first metal layer in the portion adjacent to the opening, the third metal exposed from the opening When the reflectance of the layer is smaller than the reflectance of the surface of the first metal layer adjacent to the opening, the recognition of the opening is easy.

  Preferably, in one aspect, the first metal layer is made of Au. The second metal layer is made of Cu. The third metal layer is made of Ni.

  In this case, it is easy to produce a circuit board with a mark.

  The marked circuit board of the present invention can facilitate the recognition of the mark, and even if the mark is formed, it is easy to prevent an adverse effect on the board body.

It is a top view of a circuit board. (Example) It is sectional drawing cut | disconnected along line XX of FIG. (Example) It is a top view of a laser marking wafer. (Conventional example)

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and 2.

  FIG. 1 is a plan view of the circuit board 10. FIG. 2 is a cross-sectional view taken along line XX in FIG. As shown in FIGS. 1 and 2, the circuit board 10 has a conductor pattern 30 formed on the main surface 12 a of the board body 12. The conductor pattern 30 forms a mark portion 20 that can be recognized from the outside, together with the terminal electrode 16 and the wiring pattern (not shown) of the circuit board 10. An opening 22 is formed in the mark portion 20.

  The substrate body 12 is a substrate formed of ceramic or resin, and may be a single layer substrate or a multilayer substrate.

  As shown in FIG. 2, the conductor pattern 30 has a lowermost layer 32, an intermediate layer 34, and an uppermost layer 36 laminated in this order. Each layer 32, 34, 36 of the conductor pattern 30 is a metal layer formed of metal. The uppermost layer 36 is a first metal layer, the lowermost layer 32 is a second metal layer, and the intermediate layer 34 is a third metal layer.

  The opening 22 formed in the mark portion 20 is formed by communicating a through hole penetrating the uppermost layer 36 and the intermediate layer 34 in the thickness direction and a non-through hole formed in the lowermost layer 32. The bottom surface 22 a of the opening 22 is formed by the lowermost layer 32, and the lowermost layer 32 is exposed at the bottom surface 22 a of the opening 22. The opening 22 does not penetrate the lowermost layer 32. Since the opening 22 does not reach the main surface 12 a of the substrate body 12, the main surface 12 a of the substrate body 12 is not exposed from the opening 22.

  The lowermost layer 32 of the part forming the bottom surface 22a of the opening 22 and the surface 36a of the uppermost layer 36 adjacent to the opening 22 have different light reflectivities so that they can be discriminated by visual observation or a light receiving element. Thus, it can function as a mark that can be recognized from the outside. The circuit board 10 can be identified by changing the shape, size, arrangement, and the like of the opening 22 of the mark portion 20. The opening 22 may be formed in an appropriate pattern such as a character, a figure, a barcode symbol, or a two-dimensionally arranged dot pattern.

  By increasing the difference between the reflectance of the lowermost layer 32 of the portion forming the bottom surface 22a of the opening 22 and the reflectance of the surface 36a of the uppermost layer 36 of the portion adjacent to the opening 22, the opening 22, The mark can be easily recognized.

Since the mark is formed on the conductor pattern 30 of the mark portion 20 and is not formed on the substrate body 12 itself, even if the mark is formed, it is easy to prevent an adverse effect on the substrate body 12.
Next, a specific example of the circuit board 10 will be described.

  The circuit board 10 is a collective board including a portion 14 that becomes a plurality of individual boards. In the central portion 15 of the main surface 12a of the substrate body 12, portions 14 that become individual substrates are arranged in a lattice pattern, and terminal electrodes 16 are formed on the portions 14 that become individual substrates. A mark portion 20 is formed on the peripheral edge portion 18 of the main surface 12 a of the substrate body 12.

  The terminal electrode 16 and the mark portion 20 are simultaneously formed at a predetermined position and in a predetermined shape by the lowermost layer 32, the intermediate layer 34, and the uppermost layer 36 of the conductor pattern 30 that are sequentially stacked on the main surface 12a of the substrate body 12. The

  For example, after the paste containing Cu is screen-printed on the upper surface of the laminated body in which the ceramic green sheets are laminated (that is, the portion that becomes the main surface 12a of the substrate body 12), the laminated body is baked to form the Cu lowermost layer 32. Form. Next, an Ni intermediate layer 34 is formed on the lowermost layer 32 by electroless plating, and an Au uppermost layer 36 is formed on the intermediate layer 34 by electroless plating.

  The opening 22 in the mark portion 20 is formed by a laser. That is, the surface 36 a of the uppermost layer 36 of the mark portion 20 is irradiated with a laser to form an opening 22 that penetrates the uppermost layer 36 and the intermediate layer 34 and reaches the lowermost layer 32.

  When the laser reaches the lowermost layer 32, the surface of Cu in the lowermost layer 32 changes color due to oxidation. As a result, the reflectance of the lowermost layer 32 exposed at the bottom surface 22a of the opening 22 becomes extremely smaller than the reflectance of the Au surface 36a of the uppermost layer 36 adjacent to the opening 22, and the opening 22 and its The difference in contrast with the surroundings increases. Therefore, the mark can be easily recognized.

  That is, when the reflectance of the lowermost layer 32 in the portion forming the bottom surface 22a of the opening 22 is larger than the reflectance of the surface 36a of the uppermost layer 36 in the portion adjacent to the opening 22, the illumination light is opened. The aperture 22 cannot be recognized unless it reaches the bottom surface 22a of the aperture 22 and is sufficiently reflected by the bottom surface 22a of the aperture 22. Therefore, it is difficult to recognize the mark unless a special optical system or detection device is used.

  On the other hand, when the reflectance of the lowermost layer 32 in the portion forming the bottom surface 22 a of the opening 22 is smaller than the reflectance of the surface 36 a of the uppermost layer 36 in the portion adjacent to the opening 22, the bottom surface of the opening 22. Even if the illumination light does not sufficiently reach 22a, the opening 22 can be easily recognized. Therefore, the mark can be recognized without using a special optical system or detection device.

  The mark portion 20 can be formed simply by adding a laser processing step for the opening 22. Since the discoloration of Cu is used, it is not necessary to re-plat the processed portion, and the process can be reduced. Since the mark is recognized by the difference in contrast due to Cu oxidation and discoloration, erroneous recognition of the mark due to plating scratches on the surface 36a of the uppermost layer 36 does not occur.

  As a specific example, the thickness of the uppermost layer 36 of Au is about 0.1 μm, the thickness of the intermediate layer 34 of Ni is about 4 μm, and the thickness of the lowermost layer 32 of Cu is about 10 μm. The ID code unique to the circuit board 10 is marked by forming the aperture 22 with a YAG laser having a fundamental wavelength of 1064 kHz.

  When the thickness of the uppermost layer 36 is made smaller than the thickness of the lowermost layer 32, most of the heat generated when the holes 22 are formed in the conductor pattern 30 by the laser is released through the conductor pattern 30, and is transferred to the substrate body 12. The amount of heat transferred can be reduced. Thereby, the bad influence to the board | substrate body 12 by the heat | fever generate | occur | produced when forming the opening 22 in the conductor pattern 30 with a laser can be prevented.

  When the intermediate layer 34 is provided, the heat generated when the opening 22 is formed in the conductor pattern 30 by the laser becomes more difficult to be transmitted to the substrate body 12, so that the opening 22 is formed in the conductor pattern 30 by the laser. It is possible to more effectively prevent the adverse effect on the substrate body 12 due to the heat generated in. Moreover, the power condition width when laser processing the opening 22 is widened, and laser processing becomes easy.

  When the intermediate layer 34 is provided, it is easy to ensure the bonding strength between the metal layers 32, 34, and 36 of the conductor pattern 30.

  When trying to recognize the opening 22 from the outside, the Ni intermediate layer 34 exposed from the opening 22 is also visible from the outside. Therefore, by making the reflectance of the Ni intermediate layer 34 smaller than the reflectance of the surface 36a of the uppermost layer 36 of Au adjacent to the opening 22, the reflectance of the bottom surface 22a is smaller than the reflectance of the surface 36a. The opening 22 can be easily recognized.

  As the thickness of the uppermost layer 36 of the conductor pattern 30 is smaller, the depth of the opening 22 is reduced, the laser processing amount of the opening 22 is reduced, and the amount of heat generated when the opening 22 is formed in the conductor pattern by the laser is reduced. Can be reduced. The greater the thickness of the lowermost layer 32 of the conductor pattern 30, the longer the heat transfer path that is generated when the holes 22 are formed in the conductor pattern 30 by the laser, and the less the heat is transferred to the substrate body 12. Therefore, if the thickness of the uppermost layer 36 of the conductor pattern 30 is made smaller than the thickness of the lowermost layer 32 of the conductor pattern 30, the heat applied to the substrate body 12 due to the heat generated when the holes 22 are formed in the conductor pattern 30 by the laser. Adverse effects can be effectively prevented.

  The laser processing depth of the opening 22 reaching the lowermost layer 32 is smaller as the uppermost layer 36 of the conductor pattern 30 is thinner, and the opening 22 can be formed in a short time. Even when the amount of removal of the lowermost layer 32 by the laser varies when the opening 22 is formed so that the lowermost layer 32 is exposed on the bottom surface 22a of the opening 22, the lower the lowermost layer 32 of the conductor pattern 30 is, the more the opening becomes. It is easy to prevent the bottom surface of the hole 22 from reaching the main surface 12 a of the substrate body 12. Therefore, if the thickness of the uppermost layer 36 of the conductor pattern 30 is smaller than the thickness of the lowermost layer 32 of the conductor pattern 30, the opening 22 can be easily formed.

  As the uppermost layer 36, Ag, Al or the like can be used in addition to Au. In particular, in the case of Al, it has a high reflectance even in the visible light region, so that it is easy to visually recognize the mark. As the intermediate layer 34, Pt, Sn, Tg, etc. can be used in addition to Ni. As the lowermost layer 32, Pt, Sn, Ni, Pd, Tg, etc. can be used in addition to Cu.

  <Summary> As described above, the mark portion 20 in which the opening 22 is formed in the conductor pattern 30 can facilitate the recognition of the mark, and prevents the substrate body 12 from being adversely affected even if the mark is formed. Easy to do.

  The present invention is not limited to the above embodiment, and can be implemented with various modifications.

  For example, the bottom surface of the opening may be formed in a layer other than the lowermost layer of the conductor pattern. That is, another metal layer of the conductor pattern may be disposed between the metal layer of the conductor pattern that forms the bottom surface of the opening and the main surface of the substrate body.

  Moreover, it is good also as a structure by which a some intermediate | middle layer is arrange | positioned between the uppermost layer of a conductor pattern, and the metal layer (it does not need to be the lowest layer) of the conductor pattern which forms the bottom face of an opening. On the contrary, an intermediate layer is not arranged at all between the uppermost layer of the conductor pattern in which the opening is formed and the metal layer (not necessarily the lowermost layer) of the conductor pattern that forms the bottom surface of the opening. It is also possible to do.

  The marked circuit board of the present invention can be applied not only to a collective board but also to an individual board.

10 Assembly board (circuit board)
12 Substrate body 12a Main surface 16 Terminal electrode (conductor pattern)
20 Identification mark (conductor pattern)
22 Opening 22a Bottom surface 30 Conductor pattern 32 Bottom layer (second metal layer)
34 Intermediate layer (third metal layer)
36 Top layer (first metal layer)
36a surface

Claims (5)

A substrate body;
A conductor pattern including at least two first and second metal layers laminated on a main surface of the substrate body;
In a circuit board with
The conductor pattern has a mark portion that can be recognized from the outside,
The mark portion has an opening formed from the surface of the first metal layer on the opposite side of the substrate body to the second metal layer on the substrate body side, and the opening is formed in the first metal layer. The bottom surface of the opening is formed by the second metal layer, the reflectance of the second metal layer of the portion forming the bottom surface of the opening, and the portion adjacent to the opening The marked circuit board, wherein the reflectance of the surface of the first metal layer is different. The aperture is formed by a laser;
2. The marked circuit board according to claim 1, wherein a thickness of the first metal layer of the conductor pattern is smaller than a thickness of the second metal layer of the conductor pattern.   The reflectance of the second metal layer in the portion forming the bottom surface of the opening is smaller than the reflectance of the surface of the first metal layer in the portion adjacent to the opening. The circuit board with a mark according to claim 1 or 2. The conductor pattern includes at least one third metal layer disposed between the first metal layer and the second metal layer;
In the third metal layer, an opening communicating with the opening formed in the first metal layer and the second metal layer is formed,
The thickness of the third metal layer of the conductor pattern is greater than the thickness of the first metal layer of the conductor pattern,
The reflectance of the third metal layer in a portion forming the opening is smaller than the reflectance of the surface of the first metal layer in a portion adjacent to the opening. The circuit board with a mark according to any one of 1 to 3. The first metal layer is made of Au;
The second metal layer is formed of Cu;
The marked circuit board according to claim 4, wherein the third metal layer is made of Ni.

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